EP1192353A1

EP1192353A1 - Starting and/or positioning system and method

Info

Publication number: EP1192353A1
Application number: EP01915001A
Authority: EP
Inventors: Peter Ahner; Manfred Ackermann
Original assignee: Robert Bosch GmbH
Current assignee: Robert Bosch GmbH
Priority date: 2000-02-22
Filing date: 2001-01-26
Publication date: 2002-04-03
Also published as: DE10007956A1; US20020152980A1; DE10007956B4; JP2003524115A; MXPA01010689A; WO2001063124A1

Abstract

The invention relates to a system and a method for starting and/or positioning an internal combustion engine (VM). An electric device (S/G) that is connected to the internal combustion engine via a spring/damper unit (F/D) and has a total drag torque (M1) is provided. According to the invention, the electric device (S/G) is controlled by a circuit in such a way that said electric device excites the spring/damper unit (F/D) in an oscillatory manner, using a torque (M2), whose amplitude is less than the total drag torque (M1) and that the spring/damper unit (F/D), at least in a transient state, transmits a torque to the internal combustion engine (VM), whose amplitude is greater than or equal to the total drag torque (M1).

Description

Start and / or positioning system and procedure

The invention relates to a system for staring and / or positioning an internal combustion engine with the features mentioned in the preamble of claim 1.

Furthermore, the invention relates to a method for starting and / or positioning an internal combustion engine with those mentioned in the preamble of claim 16. Features.

State of the art

Starting a combustion engine with direct drive requires a drive system that is dimensioned for the cold temperature limit temperature, which is generally assumed to be -25 ° C. Even at this cold start limit temperature, the total towing torque must be overcome to start the internal combustion engine, which is influenced, among other things, by the drag torque, the gas spring torque and the acceleration torques of the internal combustion engine. This total towing torque can be, for example, 200 Nm for a typical mid-range vehicle.

In order to reduce fuel consumption, it is already known to switch off the internal combustion engine when the vehicle is temporarily at a standstill, for example at a traffic light. to start it shortly before or while continuing to drive, so that there is a start-stop operation.

Furthermore, a so-called swing-use automat k m overrun phases can cause the internal combustion engine to be switched off / disengaged.

Such new vehicle functions as well as the now significantly increased demands on the electrical power of the Borcretz led to the development of the starter generator, an electrical machine that can be used both as a starter and as a generator. Furthermore, it is already known to preposition the internal combustion engine before starting in order to be able to better utilize the internal potential of the internal combustion engine during the starting process.

Especially when the electrical machine is a starter generator, it is crucial to reduce the torque required for the electrical machine to such an extent that the current required in generator operation is also sufficient for the start, i.e. the effort for the electrical machine and the Inverters must be minimized in terms of both the start and the generator function.

The so-called impulse start has already been proposed for this purpose. To carry out this pulse start, the internal combustion engine is connected to the starter generator via a pulse start clutch, which in turn is connected to the vehicle transmission via a clutch. The start is carried out in such a way that the flywheel mass of the starter generator is accelerated to the so-called wind-up speed by the starter generator when the pulse start clutch is open and the drive clutch is open. When this wind-up speed is reached, the impulse start clutch is closed with the drive clutch still open, so that the internal combustion engine is rapidly accelerated via the clutch torque until the clutch sticks, whereby the internal combustion engine is then prevented from stopping too quickly by the electromotive torque.

With the pulse start method, the internal combustion engine can still be started successfully even if the drive torque of the electrical machine is only 50% of the total towing torque. The level of the required drive torque of the electrical machine depends on the design of the coupling and other vehicle boundary conditions, for example the injection technology and the type of transmission.

In comparison, the so-called crankshaft direct start requires a drive torque of the electrical machine that is approximately 140% of the total towing torque.

The impulse start clutch is very complex because it has to be designed for the maximum vehicle torques and a portion of the alternating torques of the internal combustion engine. Furthermore, the injection technology has to be redesigned for the high dynamics of the pulse start. Advantages of the education

The fact that the electrical machine in the system according to the invention is controlled by a circuit in such a way that the electrical machine excites the spring-damper unit in a vibration-like manner, the arriplitude of which is smaller than the total towing torque, and that Spring-damper unit, at least in a steady state, transmits a torque to the internal combustion engine, the amplitude of which is greater than or equal to the total towing torque, the complex pulse start clutch can be omitted.

The same applies to the method according to the invention, in which the electrical machine is activated in such a way that the electrical machine excites the spring-damper unit in a vibration-like manner, the amplitude of which is smaller than the total towing torque, and in which the spring-damper Unit, at least in a steady state, transmits a torque to the internal combustion engine, the amplitude of which is greater than or equal to the total towing torque.

In the inventive system, it is advantageous if the torque with which the electric machine activates the spring-damper unit schwingungsformig, having a positive ^"value when the rotational speed of the electric machine is positive.

A positive speed is to be understood here as a speed at which the direction of rotation of the electrical machine equals the direction of rotation of the crankshaft of the combustion engine. mungscrs that results when the internal combustion engine is running.

The positive value of the torque with which the machine sees the spring-steamer unit in the form of a spray is preferably a constant value.

The torque with which the electrical machine excites the spring-damper unit preferably has a negative value if the speed of the electrical machine is negative.

A negative rotational speed of the electrical machine is to be understood here as a rotational speed that occurs when the electrical machine rotates, and is opposite 2 to the direction of rotation of the crankshaft that results when the internal combustion engine is running.

Furthermore, it can be advantageous if the torque with which the electrical machine excites the spring-steamer unit has a negative value if the speed of the electrical machine is negative and the speed of the crankshaft of the internal combustion engine is greater than or equal to zero.

It is also conceivable that the torque with which the electrical machine controls the spring-steamer unit has a negative value if the number of drums of the electrical machine is negative, the number of drums of the crankshaft of the internal combustion engine is large or equal to zero and the torque that the spring steamer E__nhειt transferred to the internal combustion engine is less than a predetermined value.

The negative value of the torque with which the electrical machine excites the spring-steamer unit can also be a constant value.

The torque with which the electrical machine excites the spring-steamer unit is preferably brought to a positive value at a negative rotational speed of the electrical machine when the speed of the crankshaft is less than zero.

A model calculation is preferably used to estimate the torque, taking into account the speed of the crankshaft of the internal combustion engine, the speed of the electrical machine and the spring characteristic of the spring of the spring / damper unit.

The spring-steamer unit preferably has a spring that is progressive with a positive twist.

The electrical machine can iron a rotor that forms the secondary mass of a two-mass flywheel.

A first speed sensor is preferably provided, which detects the speed of the crankshaft of the internal combustion engine.

A second speed sensor can detect the speed of the electrical machine. The output signal of the first speed sensor and / or the output signal of the second speed sensor is preferably supplied to the circuit.

The electrical machine is preferably connected to a vehicle transmission via a clutch.

Also in the inventive method it is advantageous when the torque, the spring-damper unit excites the ^'electric machine, has a positive value when the rotational speed of the electric machine is positive.

In this case, too, positive rpm is to be understood as the positive rpm defined above.

This positive value of the torque with which the electrical machine excites the spring-damper unit is preferably a constant value.

In the method according to the invention it can further be provided that the torque with which the electrical machine excites the spring-damper unit has a negative value if the speed of the electrical machine is negative.

Negative speed is also to be understood here as the negative speed defined above.

Furthermore, the inventive. Methods are provided that the torque with which the electrical machine excites the spring-damper unit, a negative ven value if the speed of the electrical machine is negative and the speed of the crankshaft of the internal combustion engine is greater than or equal to zero.

It can also be provided that the torque with which the electrical machine excites the spring-damper unit has a negative value if the speed of the electrical machine is negative, the speed of the crankshaft of the internal combustion engine is greater than or equal to Mull, and the torque that the spring-damper unit transmits to the internal combustion engine is less than a predetermined value.

In the method according to the invention, too, the negative value of the torque can be a constant value.

Furthermore, it can be provided that the torque with which the electrical machine excites the spring-damper unit is brought to a positive value at a negative speed of the electrical machine if the speed of the crankshaft of the internal combustion engine is less than zero.

In the method according to the invention, a model calculation is preferably used to estimate the torque, which takes into account the speed of the crankshaft of the internal combustion engine, the speed of the electrical machine, and the characteristic of the spring-damper unit. drawings

An exemplary embodiment of the invention is explained in more detail below with reference to the accompanying drawings.

Show it:

1 shows a known system for starting a combustion engine pulse;

FIG. 2 shows a schematic representation of an embodiment of the system according to the present invention;

3 shows the curve of the torque with which the electrical machine excites the spring-damper unit, the curve of the torque which the spring-damper unit transmits to the internal combustion engine, the curve of the speed of the

Crankshaft of the internal combustion engine and the curve of the speed of the electrical machine, for the area of oscillation;

FIG. 4 shows the curve of the torque with which the electrical machine excites the spring-damper unit, the curve of the torque that the spring-damper unit transmits to the internal combustion engine, the curve loss of the speed of the crankshaft of the internal combustion engine and the course of the curve of the speed of the electrical machine, for the area of the quasi-stationary drive;

Figure 5 shows the curve of the torque with which the electrical machine excites the spring-damper unit, the curve of the torque that _. the spring damper unit transmits to the internal combustion engine, the curve of the number of wires

Crankshaft of the internal combustion engine and the curve shape of the angle of rotation of the crankshaft of the internal combustion engine, for the area of the start-up;

6 shows the curve of the torque with which the electrical machine excites the spring-steamer unit, the curve of the torque which the spring-steamer unit transmits to the combustion engine, the curve of the speed of the crankshaft of the internal combustion engine and the curve of the Angle of rotation of the crankshaft of the internal combustion engine, for the area of the quasi-stationary drive;

In FIGS. 3 to β, the time sec is plotted on the horizontal axis 10, the torque in Nm is plotted on the left vertical axis 11, and the speed in 1 / min is plotted on the right vertical axis 12. In Figures 5 and 6 is on the right vertical axis 12 is also given the P _rDεl..ellendreh- win el °.

FIG. 1 shows a known system for starting a combustion motor VM, which is connected via a pulse start clutch ISK to an electrical machine in the form of a starter generator S / G. The starter generator S / G is connected via a clutch K to a vehicle body.

In the system shown in FIG. 1, the start of the internal combustion engine proceeds as described at the beginning.

Description of the exemplary embodiment

FIG. 2 shows an exemplary embodiment of the present invention. The crankshaft V ^' / i of an internal combustion engine VM is connected to an electrical machine in the form of a start generator S / G via a spring / steam unit F / D. The speed D2 of the crankshaft KW of the internal combustion engine VM is detected by a first speed sensor DG1. The speed D1 of the starter generator S / G is also detected by a second speed sensor DG2.

The starter generator S / G is connected via a clutch K to a fan gear transmission FG, the clutch K preferably being disengaged during the starting or positioning process. Regardless of whether or not the electrical machine is in the form of a starter generator S / G, the electrical machine can be a machine with a gear without a reduction gear.

In this embodiment, the positioning and / or starting of the pre-identification motor VM is carried out directly by a type of drive of the electrical machine S / G with periodic oscillation excitation and the torque transmission via the Fεdεr-Dampfer-E hεit F / D.

The spring / steam unit E / F / D can either be a torsion spring / steam unit which is already used for damping the initial damping or a modified design of this unit.

Dabεi is diε electric machine S / G ^"rbindung with the spring-Dampfεr-E hεit F / D correct phase driven, the Scnwmgung wodurcn sowεit excited /; ιro that the internal combustion engine ICE in peπodiscnen Zeitonasen via the torsion spring of the spring damper Ξinheit F / D is turned on.

A positive torque M2 of the starter generator S / G is sufficient for triggering control. However, in the border area, with extremely small torques M2 of the starter generator S / G, positive and negative torques M2 are more favorable in relation to the total towing torque M1.

As mentioned, the speed D2 of the crankshaft KVJ of the combustion engine VM is ensor by a first reh erstenahls DG1 is detected while the speed Dl of the electrical machine S / G is detected by a second speed sensor DG2.

The spring torque can be estimated using the following calculation model:

M _Fed e _r = ΔΦ * C _Fsdεr (ΔΦ)

The following applies:

ΔΦ = JΔωdz

Where Δc is the difference between the number D2 of the crankshaft KW of the internal combustion engine VM and the speed Dl of the electrical machine S / G.

In this calculation model, all energy-relevant variables are constantly under control, so that drive control of the electrical machine in the form of a start generator S / G can take place in accordance with the following rules:

1. First, the vibration in both directions of rotation of the starter generator S / G can be positively excited with bipolar control (by energy supply);

1.1 At positive speeds of the starter generator S / G, positive torques M2 of the starter generator S / G are used; 1.2 At negative speeds of the starter generator S / G that are limited in time, negative torques M2 of the starter generator S / G are used;

2. If the spring torque M3 has negative values, the starter generator S / G must be braked in good time in order to prevent the internal combustion engine VM from turning back.

In Figures 3 and 4, the curves of the torque M2, with which the electrical machine S / G excites the spring-damper unit F / D, the torque M3, which the spring-damper unit F / D on the internal combustion engine VM transfers, the speed Dl of the electrical machine S / G and the Drεhzahl D2 of the crankshaft KW of the internal combustion engine VM shown.

FIGS. 5 and 6 show the same curves, with the exception that instead of the number of wires Dl of the electrical machine S / G, the angle of rotation W2 of the crankshaft is shown.

The curves apply to an internal combustion engine that has a total towing torque Ml of 150 Nm. This corresponds to the total towing torque of a mid-range engine at -25 ° C. The torque M2 with which the electrical machine S / G excites the spring-damper unit corresponds to 50 Nm in the case shown.

The torsional stiffness and the damping values of the spring / damper unit F / D were determined according to values from Fεdεr-Därαpfεr- systems, which are used to decouple the alternating torque. te of the internal combustion engine VM between the Vercrεnnungsmotor VM and the vehicle transmission FG are used.

When the electrical machine is turned on in the form of a starter generator S / G and the clutch K is open, the internal combustion engine VM initially stops in static friction. The starter generator S / G pulls the torsion springs against the holding torque.

The torque M2, with which the starter generator excites the spring-damper emission F / D, is always fully controlled with excitation at a positive number of revolutions Dl, while at negative speed Dl only the phase with positive torsional torque is used.

To reduce the power loss, the starter generator S / G was only driven with full positive or negative torque M2 or with a torque of zero.

The torque M3, which the spring-steamer unit F / D transmits to the internal combustion engine VM, exceeds for the first time in FIG. 3 at the time mark of 0.12 seconds the value of the total drag torque Ml, so that the crankshaft KW is the first at this time Turned on as shown in the curve D2.

In the next negative half-period, the crankshaft KW will turn back very weakly for a short time, but this is not a problem here. This weak turning back of the crankshaft KW can also be prevented by briefly counter-phase activation of the starter generator S / G if this brings advantages.

It can be seen in FIGS. 4 and 6 how the vibration stabilizes and that from a point in time of about 0.5 seconds a quasi-stationary pulsed forward movement of the crankshaft KW occurs, the pulse frequency in the illustrated case being approximately 12 Hz and automatically adapts to the value of the torsional damper natural frequency.

The average speed of the crankshaft KW also results from the angle of rotation curve W2, a speed of 22 l / minute being achieved in the case shown.

The limits of the torque of the starter generator S / G for positioning in the desired direction of rotation iiεgεn with damping, which are common in a two-mass flywheel, are approximately 5 times below the total attachment torque Ml. «• This can also be shown by a simulation calculation.

Claims

claims

1. System for starting and / or positioning an internal combustion engine (VM) with an electrical machine

(S / G), which is connected via εinε spring-damper unit (F / D) to the internal combustion engine, which has a total towing torque (Ml), characterized in that the electrical machine (S / G) is controlled by a circuit in this way is that the electrical machine (S / G) vibrates the Fεdεr-D mpf r unit (F / D) with a torque (M2) whose amplitude is smaller than the total towing torque (Ml), and that the Fedεr -Dampfεr unit (F / D), at least in a steady state, transmits a torque (M3) to the internal combustion engine (VM), the amplitude of which is greater than or equal to the total towing torque (Ml).

2. System according to. Claim 1, characterized in that the torque (M2) has a positive value if the speed (Dl) of the electrical machine (S / G) is positive.

3. System according to one of the preceding claims, characterized in that the positive value of the torque (M2) is a constant value.

4. System according to any one of the preceding claims, characterized in that the torque (M2) has a negative value if the speed (Dl) of the electrical machine (S / G) is negative.

5. System according to any one of the preceding claims, characterized in that the torque (M2) has a negative value if the number of rotations (Dl) of the electrical machine (S / G) is negative and the speed (D2) of the crankshaft (KW) dεs Combustion engine (VM) is greater than or equal to I _11.

6. System according to one of the preceding claims, characterized in that the torque (M2) has a negative ^' value if the number of wires (Dl) of the electrical machine (S / G) is negative, the number of wires (D2) of the crankshaft ( KW) of the internal combustion engine 'VM) is greater than or equal to Nαll and the torque (M3) is less than a predetermined value.

7. System according to any one of the preceding claims, characterized in that the negative value of the torque (M2; is a constant value.

8. System according to one of the preceding claims, characterized in that the torque (M2) at a negative speed (Dl) of the electrical machine (S / G) is brought to a positive value when the speed (D2) of the crankshaft (KW ) is internal combustion engine (VM) small gauze.

9. System according to the preceding claims, characterized in that for estimating the torque (M3) a model calculation εmgεsεtzt, diε diε speed (D2) of the crankshaft (KW) of the internal combustion engine (VM), the speed (Dl) of the electric machine (S / G) and the spring line of the spring of the spring-steamer unit (F / D) are taken into account.

10. System according to one of the preceding claims, characterized in that the spring-steamer unit

(F / D) has a spring which is progressive with a positive twist.

11. System according to a previous one. Claims, characterized in that the electrical machine (S / G) has a rotor which forms the Ξe and .arm mass εinεs two-mass flywheels.

12. System according to εinεm dεr prehεrgεhεnden claims, characterized in that a first speed sensor

(DG1) is provided, which detects the speed (D2) of the crankshaft (KW) of the internal combustion engine (VM).

13. System according to one of the previous claims, characterized in that a second speed sensor

(DG2) is provided, which detects the rotational speed (Dl) of the electrical machine (S / G).

14. System according to one of the preceding claims, characterized in that the circuit receives the output signal of the first speed sensor (DG1) and / or the output signal of the second speed sensor (DG2).

15. S stem according to one of the preceding claims, characterized in that the electrical machine (S / G) via ε e coupling (K) with a vehicle transmission (FG)

16. experienced for starting and / or positioning an internal combustion engine (VM), which comprises the control of the electrical machine (S / G), which is connected to an internal combustion engine via a spring-steam unit (F / D), which has a total connecting torque (Ml), characterized in that the control takes place dεrart, the electrical machine (S / G) vibrates the spring-steamer unit (F / D) with a torque (M2), its amplitude is smaller than the total drag torque (Ml), and that the spring / damper unit (F / D), at least in a steady state, transmits a torque (M3) to the internal combustion engine (VM), the amplitude of which is greater than or equal to the total drag torque ( Ml) is.

17. The method according to claim 16, characterized in that the torque (M2) has a positive value if o_e speed (Dl) of the electrical machine (S / G) DOSltl ^" .

18. The method according to claim 16 or 17, characterized in that the positive value of the torque (M2) is a constant value.

19. The method according to any one of claims 16 to 18, characterized in that the torque (M2) has a negative value if the speed (Dl) of the electrical machine (S / G) is negative.

20. The method according to any one of claims 16 to 19, characterized in that the torque (M2) εinεn has a negative value if the speed (Dl) of the electrical machine (S / G) is negative and the speed (D2) of the crankshaft ( KW) of the internal combustion engine ^' VM) is greater than or equal to zero.

21. The method according to any one of claims 16 to 20, characterized in that the torque (M2) has a negative value when the speed (Dl) of the electric machine (S / G) is negative, the number of wires (D2) of the crankshaft (KW ) of the internal combustion engine (VM) is greater than or equal to zero and the torque (M3) is less than a predetermined value.

22. Method according to one of claims 16 to 21, characterized in that the negative value of the torque (M2) is a constant value.

23. Vεrfahrεn according to any one of claims 16 to 22, characterized in that the torque (M2) at a negative Drεhzahl (Dl) dεr εlεktrischεn machine (S / G) is brought to a positive value when diε Drεhzahl (D2) of the crankshaft is less than zero.

24. The method according to one of claims 16 to 23, characterized in that for estimating the torque (M3), a model calculation is used which represents the speed (D2) of the crankshaft (KW) of the combustion engine (VM), the speed (Dl) of the electrical machine (S / G) and the spring characteristic of the spring of the spring-damper unit (F / D) are taken into account.